Lubricating compositions



United States Patent LUBRICATIN G COMPOSITIONS Werner Miiller, Koln, and Roderich Raue, Leverkusen,

Germany, assignors to Farbenfahriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application April 14, 1954 Serial No. 423,220

Claims priority, application Germany April 16, 1953 Claims. (Cl. 25251.5)

The present invention relates to lubricating compositions; more particularly it concerns lubricating compositions containing a lubricant and an amide derived from an amine and an aromatic ortho-hydroxy-carboxylic acid.

The lubricating compositions of the invention are very stable under storage conditions and to oxidizing influences so that they can be used with special advantage in internal combustion engines, in gearing systems, as cutting fluids for machine cutting tools, as turbine oils or transformer oils or in other operations where lubricants are employed.

The term lubricant as used throughout the specification and claims is intended to refer to an oil or fat as it is or may be used as lubricating agent, in the first line it means a mineral oil; the term aromatic ortho-hydroxy carboxylic acid includes the ortho-hydroxy-carboxylic acidsper se and the substitution products of the orthohydroxy-carboxylic acids containing for instance an alkyl group, a halogen or a further hydroxyl group, the amine is especially a primary amine, preferably an amine whose nitrogen atom is linked to a secondary or tertiary carbon atom.

The amides of aromatic ortho-hydroxy-carboxylic acids forming part of the lubricating compositions of the invention are more or less weakly colored compounds which are easily accessible; they are easily soluble and highly active in oils and fats and are thus distinguished from the known additives to lubricants, which do not possess all these advantages at the same rate.

The amounts of the amides to be added to the lubricants can easily be determined by preliminary tests; in general, 1-5 parts of the amide are sufiicient for 1000 parts of the lubricant, but the amounts may often be varied within wide limits. Instead of uniform amides, also mixtures of amides may be employed according to the invention.

The amides of aromatic ortho-hydroxy-carboxylic acids can be obtained by any suitable manner, for in- Stance by reacting ortho-hydroxy-carboxylic acid halides with the relevant amines at a molecular ratio of 1:2 in the presence or in the absence of a solvent or diluent at normal or elevated temperature; in this reaction one molecular part of the amines forms a salt with the hydrogen halide which is split off; in many cases, it is also possible to obtain the amides of the aromatic orthohydroxy-carboxylic acids by heating the aromatic orthohydroxy-carboxylic acids assuch with the amines in the presence or in the absence of high boiling solvents or diluents, if necessary with the aid of compounds binding the water formed during the reaction. The amides Patented Aug. 19, 1958 obtained can easily be purified by distilling otf first any solvents or diluents, removing any hydrogen halide with Water or aqueous sodium hydroxide and distilling ofi. the water, whereupon the amides themselves are subjected to fractional distillation in vacuo.

Aromatic ortho-hydroxy-carboxylic acids suitable as acid components of the amides forming part of the lubricating compositions are for instance salicylic acid, 3- chloro-2-hydroXy-benzoic acid, 5-chlor0-2-hydroxy-benzoic acid, 3-methyl-2-hydroxy-benzoic acid, 5-chloro-3- methyl-2-hydroxy-benzoic acid, 5- or 'y-resorcylic acid, Z-hydroxy-l-naphthoic acid, l-hydroxy-Z-naphthoic acid, 3-hydroxy-2-naphthoic acid and 4-chloro-3-hydroxy-2- naphthoic acid.

Suitable amines which may be employed for the formation of the amide component of the lubricating compositions of the present invention are for instance isopropylamine, 2-aminobutane, 3,3-dimethyl-2-aminobutane, 2,4-dimethyl-3-aminopentane, cyclohexylamine, 2-.

Example 1 2 parts of the amide of an aromatic ortho-hydroxycarboxylic acid described below are dissolved with stirring in 1000 parts of a mineral oil; the oil proves to be very stable against oxidizing influences.

The amide is prepared as follows:

62 parts of 5-chloro-3-methyl-2-hydroxy benzoic acid are added within an hour while stirring to a mixture of 50 parts of thionyl chloride and parts of benzene heated to C. The reaction mixture is heated at 90100 C. for 22 hours and kept at 90l00 C. for a further 25 hours after the addition of 20 parts of thionyl chloride. Thereupon the solution is evaporated in vacuo until all the thionyl chloride is evaporated, and then diluted with parts of benzene. While stirring and cooling the solution so that the temperature does not exceed 30 C., 106 parts of a parafiin amine containing a chain in the molecule of about 10 carbon atoms and bearing the amino group approximately in the middle of the chain are added. The reaction mixture is heated on the water bath for an hour to complete the formation of the amide. After cooling the solution at normal temperature it is shaken first with dilute sodium hydroxide solution and then with water. Thereupon the benzene and non-consumed paraflin amine are distilled off in a low vacuo; the paraffin amide of the S-chloro- 3-methyl-2-hydroxy-benzoic acid is obtained by distillation in a high vacuo in the form of a light-yellow oil having a boiling point of -l93 C. at 0.6 mm. Hg.

Composition: C H O NCl. Calculated for: C, 66.4%; H, 8.62%; O, 9.85%; N, 4.32%; C1, 10.78%. Found: C, 66.3%; H, 8.55%; O, 10.60%; N, 4.45%; Cl, 10.60%. I

Instead of the amide of the ortho-hydroxy-carboxylic acid described above, the following amides may be used in the lubricating compositions.

Melting Boiling Point in 0. Summation Amide obtained from Point and mm. Hg Formula acc.

" O. to analysis salicylic acid and a mixture of amines with a carbon 170-196" C./2.4 mm C11H21O2N chain having, on an average, 10 carbon atoms. -0111oro-2-hydroxy-benzoic acid and a mixture of 174-202" C./0.9 mm CnHzaOzNCl amines with a carbon chain having, on an average, carbon atoms. 5-chloro-2-hydroxy-benzoic acid and a mixture of 198-232" C./0.8 mm CzzHaaOzNGl amines with a carbon chain having, on an average, carbon atoms. 3-methy1-2-hydroxy-benzoic acid and a mixture of 183-233" O.l1.1 mm CzaHeqOrN amines with a carbon chain having, on an average, 15 carbon atoms. 5-ch1oro-3-methy1-2-hydroxy-benzoic acid and a 182-232" C./0.7 mm CzaHasOzNCl mixture of amines with a carbon chain having, on

an average, 15 carbon atoms. 5-chloro-3-methyl-2-hydroxy-benzoic acid and the mixture of 2-hepty1amine and 2-octylamine.

5-(ihl0ro-13-methyl-2-hydroxy-benzolc acid and 4 129-130.. 189-194" C./l.6 mm CmHzgOzNCl epty amine. 5-chloro-3-methyl-2-hydroxy-benzoic acid and 2,4- 134-136.. 150-162" C./0.6 mm OrsHrzOzNOl V dimethyl-3-amiuopentane. 4 5-chloro-3-methyl-2-hydroxy-benzoic-acid and 3,3- 85-87.... 164-168" C.l0.5 mm CuHzoOzNCl dimethyl-Z-aminobutane. 5-clhlorif-3-methyl-2-hydroxy-benzoic acid and cyclo- 145-146.. 174-194" O./0.8 mm CuHisOzNCl exy amine. 54gb]oro-3 methyl-2-hydroxy-bcnzoic acid and 2- 87-88.... 155-167" 040.8 mm CnHmOzNCl uty -amine. 3-chloro-2-hydroxy-benzoic acid and a mixture of 193-235" C.l0.5 mm C22HaeO2NC1 amines with a carbon chain having on an average, 15 carbon atoms.

172-191" C./0.8 mm

G15,s zaOzNOl These amines of ortho-hydroxy-carboxylic acids can be less by recrystallizing from alcohol.

obtained in a manner analogous to that described above; if desired, the chloride of the ortho-hydroxy-carboxylic acid is purified by distillation in vacuo prior to the reaction With the amine.

Example 2 1000 parts of a gear oil are stirred with 2 parts of the amide of 3-hydroxy-2-naphthoic acid described below until complete solution occurs; the stability of the oil against influences is greatly improved.

The amide of 3-hydroxy-2-naphthoic acid is prepared Melting Boiling Point in C. Summation Amide obtained from Point and mm. Hg Formula acc.

in O. to analysis 3-hydroxy-2-naphthoic acid and 2-amino-butane.. 119-121.. 195-201" O./1 mm.- C15H11ON 3-hydroxy-2-naphthoic acid and cyclohexylamine.. 168-169.. 232-236" C./1.4 mm C17H1902N 3-hydroxy-2-naphthoic acid and 4-amino-heptane.-.- 121-123.- 220-223" C. 0.8 mm CisHzaOzN 3-hydroxy-2-naphthoic acid and a mixture of 2- 218225 C./1 mm.- (hMHHOZN amino-heptane and Z-aminooctane. S-hydroxy-Z-naphthoic acid and a mixture of amines 240-262" C./1.5 mm 021E290 2N with a carbon chain having on the average 10 carbon atoms. 3-hydroxy-2-naphthoic acid and a mixture of amines 200-260" O./1.3 mm CzaHaoOzN with a carbon chain havmg on the average 15 can hon atoms. z-hydroxy-i-naphthoic acld and a mixture of amines 142-178 O./0.85 mm..--. CziHzeOzN \gith a; carbon chain having on the average 10 caron a oms.

in the following manner:

65.5 parts of thionyl chloride are dropped quickly at 80 C. with stirring into a mixture of 94 parts of 3-hydroxy-Z-naphthoic acid, 100 parts of toluene and 0.3 part of aluminium chloride. The reaction mixture is kept at 80 C. for 2'hours whereby the acid is dissolved. The solution is then filtered 01f from the little residue left and cooled to 0 C. The chloride of the 3-hydroxy- Z-naphthoic acid separates in the form of a yellow colored crystal mass; it is filtered off, Washed with little toluene and then with abundant ligroine and dried.

20.6 parts of the chloride obtained are dissolved in 75 parts of benzene and the solution is' slowly mixed while stirring with 22.6 parts of 2,4-dimethyl-3-aminopentane of the boiling point of 124-126" C.; in this reaction the temperature should not exceed 30 C. By further Working up the reaction mixture according to Example 1, the corresponding amide of the 3-hydroxy- 2-naphthoic acid is obtained as light-yellow oil of the boiling point 207-215 C. at 1.4 mm. Hg, which solidifies to light-yellow crystals which can be obtained color- Example 3 1000 parts of a mineral oil are mixed while stirring with 2 parts of an amide of 3-methyl-2-hydr0xybenzoic acid which is prepared in the following manner:

A mixture is made from parts of xylene, 50 parts of 3-methyl-2-hydroxy-benzoic acid and 53 parts of a paraflin amine whose molecule has a chain of approximately 10 carbon atoms and bearsthe amino group approximately in the middle of the chain; such a paraflin amine can be obtained by ketonizing fatty acids of 4-6 carbon atoms and aminizing the reaction products by means of ammonia and hydrogen. Into this mixture 50 1 parts of thionyl chloride are dropped at 90-95 C. within 3 hours. Thereupon the temperature is gradually raised to C. in the course of 6 hours and the reaction mixture stirred at this temperature for a further 24 hours. Finally, the mixture is distilled. At 1.1 mm. Hg 'and 174- 201 C., a light-yellow oil is obtained; its composition corresponds to the summation formula C H O N.

Calculated for: C, 74.3%; H, 9.97%; O, 11.0%; N,

wherein X represents an acyl radical of an aromatic orthohydroxy carboxylic acid whereas R stands for an aliphatic hydrocarbon radical and R for a member of the group consisting of hydrogen and an aliphatic hydrocarbon radical.

2. Composition of claim 1 wherein R is an aliphatic hydrocarbon radical which is linked to N by a secondary carbon atom.

3. Composition of claim 1 wherein R is an aliphatic hydrocarbon radical which is linked to N by a tertiary carbon atom.

4. Composition of claim 1 wherein R is an aliphatic hydrocarbon radical which is linked to N by a secondary carbon atom positioned approximately in the middle of a chain of about 1015 carbon atoms.

5. Composition of claim 1 wherein X is an acyl radical of an aromatic ortho-hydroxy carboxylic acid substituted by at least one member of-the group consisting of halogen and an alkyl radical.

6. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, from 0.1-0.5% by weight of said oil, of an amide of the general formula of a mineral lubricating oil and 0.1-0.5% by weight of said oil, of an amide having the general formula mo on wherein R is an aliphatic hydrocarbon radical and R is a member of the group consisting of hydrogen and an aliphatic hydrocarbon radical.

8. A lubricant composition comprising a major amount of a mineral lubricating oil and from 01-05% by Weight of said oil, of an amide of the formula HaC OH CgHg Cl 9. A lubricant composition comprising a major amount of a mineral lubricating oil and from 01-05% by Weight of said oil, of an amide of the formula I Ha)s 10. A lubricant composition comprising a major amount of a mineral lubricating oil and from 0.10.5% by weight of said oil, of an amide of the formula CH OH OH 1!):

References Cited in the file of this patent UNITED STATES PATENTS 2,337,380 Finley et al. Dec. 21, 1943 2,366,074 Wasson et a1 Dec. 26, 1944 2,401,957 Pederson June 11, 1946 2,403,067 Fischer July 2, 1946 FOREIGN PATENTS 748,169 Great Britain Apr. 25, 1956 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL AND A MINOR AMOUNT, SUFFICIENT TO INHIBIT THE OXIDATIVE DETERIORATION OF SAID OIL, OF AN AMIDE OF THE GENERAL FORMULA 